Mate, this week I test rode both a Speedmaster and an America.
To my way of thinking the only real difference is that the Speedmaster pulls you closer to the bars thereby giving less wind resistance.
In my case I rode it with straight arms whereas on the America they were bent at the elbow. The idea being to set you up better for speed.
I found that uncomfortable and that I tended to grip harder leaving my hands sore. Being new to such bikes I was probably gripping to hard.
The America certainly seemed to be much cooler and more comfortable to ride.
Given that both bikes are identical in most other aspects, I've gone for the America and pick it up tomorrow.
However, as many wiser riders have said to me in this forum, try both and buy what feels best for you.
